Datacenters and other facilities often have large data storage capabilities. Sometimes these capabilities are implemented using tape library units. The library units include tape cartridges (sometimes alternatively termed cassettes), which can be removed from and replaced to the library units as needed.
So that the tape library units can be used efficiently and reliably, it is important that the tape cartridges stay correctly positioned in the library units when the cartridges are not in use, even in light of movement of the library, for example during seismic activity or during movement of surrounding equipment. However, the cartridges also need to be readily available for use.